A boost converter with a transformer instead of an inductor is basically a flyback converter. Since you can choose your ratios, you could pick a 2.8:25 ratio. The transformer primary is connected exactly the same way as the inductor was, but the discharge cycle now happens from the secondary winding.
This would mean that at maximum voltage, the duty cycle is 50%. So if you have a 50% duty cycle on the secondary, then for a 2A average output, you would need 4 A peak in the secondary or more.
What I forgot to explain properly is that with the transformer ratio, it would mean 36A peak in the transformer primary or more. It was 20A or more when the primary had a 90% charging duty cycle. It makes sense that it goes up to about 36A with a 50% charging duty cycle.
So the transformer can be designed to give you much less ripple current in the secondary circuit at the expense of more ripple and a higher peak current in the primary. Sometimes it is worth the effort if the quality of the output, or the ESR peak current rating of the secondary components is the prime concern. Transformers are always more expensive then inductors and tend to be much harder to design.
Richard.